GENETIC-ANALYSIS OF THE CIRCADIAN SYSTEM OF MAMMALS - PROPERTIES AND PROSPECTS

Two autosomal semidominant mutations that affect the period of the cir cadian clock have been discovered in rodents. In the golden hamster th e tau mutation shortens the period from 24 h (wild-type) to 22 h (hete rozygote) and 20 h (homozygote). In the mouse the Clock mutation lengt hens the period by more than 1 h (heterozygote) and initially by about 4 h in homozygotes, which then become arrhythmic within 3 weeks. Thes e mutations, and the others that will surely be identified by further screening, will provide powerful tools for the dissection of the mamma lian clock at both the molecular and the system level.